Apparatus for the production of a sheet of tobacco

ABSTRACT

Apparatus for the production of sheet tobacco is disclosed which comprises a conveyor, means for spraying a mixture of powdered tobacco, water and bonding agent on the conveyor and means for removing the sheet after formation from the conveyor. The spraying means is constituted of a steam source, conduit and nozzle with an injection means for introducing an additive into the steam conduit. Cooling means are provided in the apparatus on the opposite side of the conveyor from the spray means.

United States Patent [151 3,704,715

Buchmann et al. 1 Dec. 5, 1972 1541 APPARATUS FOR THE PRODUCTION OF A SHEET OF TOBACCO [72] Inventors: Paul Buchmann, Basel, Switzerland; Monique Beringer, St. Louis, France 10/1945 Saslow ..117/l05.5 12/1970 Key,llletal. ..131/136X Primary Examiner-Melvin D. Rein [73] Assignee: Tamag Basel AG, Basel, Switzerland AttorneyKarl F. Ross 22 Filed: Sept. 24, 1970 I 211 App]. No.: 74,989 [57] ABSTRACT Apparatus for the production of sheet tobacco is disclosed which comprises a conveyor, means for spray- [30] Foreign Application Priority Data I ing a mixture of powdered tobacco, water and bond- Nov. 10, 1969 Germany ..l.; ..P 19 56 402.4 g agent on the conveyor and means f removing the [52] U 8 Cl 131/140 C 131/144 sheet after formation from the conveyor. The spraying [51 rn'tfc1.1111111111111111111111111111 ..A2 4b 03/14 means is constituted of a Steam Source conduit and nozzle with an injection means for introducing an additive into the steam conduit. Cooling means are provided in the apparatus on the opposite side of the con- [58]. Field of Search ....131/l33, 138, 140, 17; 34/37,

[56] References Cited veyor from the spray means.

UNITED STATES PATENTS 3 Claims, 3 Drawing Figures 3,194,245 7/1965 Clarke ..131/140C 23 r .0 3L 2 s 17 20 29 5 15\ 19 28 30 20o 31 3'7 35 so 11.

' PATENTEDnEc 5 I972 IN VEN TOR. 5

Attorr.

APPARATUS FOR THE PRODUCTION OF A SHEET OF TOBACCO FIELD OF THE INVENTION The invention relates to an apparatus for producing a sheet of tobacco.

BACKGROUND OF THE INVENTION According to one known process for producing tobacco sheets, a layer of water, followed by a layer of tobacco powder, a layer of bonding agent and then a second layer .of tobacco powder are applied to a backing sheet. In this way, a pulpy layer is produced on the backing sheet. According to a further known process a pulp is produced from the same substances and then applied to the backing sheet as a prepared coating. In both casesthe damp pulp is dried on the sheet by the action of heat, which causes it to solidify and to adhere to the backing sheet. To enable the solidified sheet to be detached therefrom, it is dampened again, by blowing water vapor thereagainst.

In the manufacture of tobacco sheet, it is known to add plasticizer substances, such as glycerine, which reduce the brittleness of the completed sheet. In the process described above, which is based on a pre-mixe'd tobacco pulp, the plasticizer is added to this tobacco pulp prior to the spreading thereof on the backing sheet. It is also known to spray the plasticizer on the tobacco sheet while it is still located on the backing sheet and moreover, after it has been set by drying. By adding the plasticizer to the pulp, it passes through the subsequent operational stages applied to the pulp, and is able to interfere therewith. The plasticizer may itself be subject to structural changes. In processes not based on a pulp, such as in the prior-art systems described above, this known method of addition is eliminated. The addition of the plasticizer by spraying onto the sheet necessitates a considerable outlay on the spraying device itself, since the device must spray the plasticizer onto the sheet in a finely divided manner while, in order to obtain the desired results, the spray must be uniformly distributed over the sheet. Moreover, in such known methods, much of theplasticizer is lost.

OBJECT OF THE INVENTION It is an object of the present invention to provide a process and an apparatus for producing a sheet of tobacco wherein the plasticizer, and any other desired additives such as a flavor improver, are added during the latter stages of the production process, thereby reducing costs.

SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a system for the production of a sheet of admixing may be carried out in such a manner that the water to be evaporated on the sheet has glycerine mixed therewith or alternatively, the glycerine is introduced into the vapor phase of the water. The invention moreover uses the property that the additives, when admixed with the water vapor, are spread uniformly and proportionally.

Preferably, 30 grams plasticizer are admixed with the steam per kilogram of tobacco to be treated. Such relatively small quantities will suffice, due to the method of introducing the plasticizer to the steam.

Advantageously the additive is injected into the stream of steam. By so doing, the additives absorb heat from the steam. For this reason, it is advisable to utilize superheated steam to prevent a condensate from being formed at the point of admixture. However, since the quantity of additive utilized is relatively small, such heat losses through condensation are almost insignificant. I I

The additives themselves maybe introduced into the steam in any desired physical state. They may be cold, pre-heated or vaporized. They may also be concentrated or dissolved, for example, in alcohol or water.

Further preferably, the additive is injected into the stream of steam by a venturi effect. The venturi effect occurs when the steam flow is allowed to pass through a constriction in a pipe and a second pipe enters at the constriction. Due to the reduction of pressure at the constriction a suction effect is caused in the second duct. The additive is therefore induced to flow into the main flow.

The backing sheet is preferably cooled by spraying at with condensed steam. This accelerates the condensation of the steam and the additives onto the tobacco.

Thus the invention provides an apparatus for the production of a sheet of tobacco comprising a conveyor means, means for spreading a layer of powdered tobacco, water and a bonding agent thereon, means for drying the layer arranged in series with the spreading means in the direction of travel of the conveyor, means for spraying steam against the dried layer, andmeans for removing the layer from the conveyor means wherein the spraying means comprises a steam source, a conduit and steam jet nozzles. In addition means are provided for injecting an additive into the spraying means. Although other additives may be employed, the present invention is preferably utilized for the addition of plasticizers. Glycerine and sorbitol are the preferred plasticizers employed.

DESCRIPTION OF THE DRAWING The invention will be further described, purely by way of example, with reference to the accompanying drawing, in which:

FIG. 1 is a perspective view of an apparatus for producing a sheet of tobacco in accordance with the present invention,

FIG. 2 is a perspective view, partially in section, of a plasticizer apportioner forming part of apparatus shown in FIG. 1 and FIG. 3 is a steam nozzle suitable for use in a modified embodiment in which the plasticizer is admixed in the steam nozzle.

SPECIFIC DESCRIPTION As shown in FIG. 1, an endless, rotatably driven, steel belt 1 is passed in the direction of arrow 4 over rollers 2 and 3. Various sections of the apparatus are generally indicated by numerals 5,6,7,8 and 9. A spreader is denoted by 5, a hot air drier 6, an evaporator 7, a cooling device 8, and a scraper 9. A sheet takeup drum is rotatably driven in the direction of arrow 11. The spreader 5 substantially consistsof an elongated funnel 12, the mouth thereof extending over substantially the whole width of the steel belt 1. The funnel 12 is charged'with a pulp 14 formed of tobacco, water and a bonding agent. The pulp is spread in a layer 15 over the upper-surface of the steel belt 1 and passes therealong into the hot air drier 6. The hot air drier 6 has four chambers 16, 17,18 and 19 which chambers have a front wall a. In FIG. 1, this front wall 20a has been removed so as to show the chambers. These chambers are interconnected in pairs. As shown in FIG. I, chambers 16 and 17 are interconnected as are chambers I8 and 19. The chambers 16,17,18 and 19 are open at their lower ends and extend substantially over the whole width of belt 1. Each pair ofchambers are provided with an inlet and an outlet pipe, the inlet pipe being-disposed on one chamber and the outletpipe being disposedon the other chamber of the pair. Thus, chamber 17 is provided with an inlet pipe 21 whilst chamber 16 is provided with an outlet pipe 22. Similarly, chamber 19 is provided with an inlet pipe 20 whilst chamber 18 is provided with an outlet pipe 23. Apart from the above, the chambers are closed in all respects. Inlet pipes 20 and 21 are connected to the output of a hot air blower (not shown) while outlet pipes 22 and 23 open into the atmosphere. Thus, as indicated by the arrows, hot air flows, in the vicinity of the layer 15, in a direction substantially opposite to the direction of travel of the layer. The layer 15 is dried and set thereby. The set layer or sheet then passes to the evaporator7 and the cooling device 8. The cooling device 8 consists of a plate 25 mounted beneath the underside of the belt I. This plate 25 extends over substantially the whole width of the'steel belt and is fed via a pipe 26 from a unit, not shown, with a coolant, which coolant is removed therefrom via pipe 27. A hood 28 is arranged above the belt 1 substantially opposite plate 25, which hood extends substantially over the whole width of the belt, and is open at the bottom.

A steam supply conduit 29 extends into the center of the hood and is provided with a steam jet 30 such that the spray 31 therefrom is uniformly distributed over substantially the entire width of the layer 15. The steam supply conduit 29 is connected to a steam source 32,

which latter supplied slightly superheated steam under pressure. The throughput thereof is adjustable by means of regulator 33. The conduit 29 is provided with a constriction 34, this constriction being provided at the point where a riser pipe 35 enters pipe 29. Riser pipe 35 extends into an open tank 36 filled with glycerine 37. An adjustable throttle valve 38 is provided on the riser pipe 35. During operation, steam flows from the source 32 to the nozzle 30. Due to the venturi effect occurring at constriction 34, glycerine is drawn vertically upwards from the tank 36 through riser pipe 35 and is thereby injected into the steam flow and is sprayed onto the layer therewith. No condensa- 4 tion occurs in the pipes, due to the fact that the steam provided by the steam sourceis slightly superheated. During travel from the constriction 34 to the nozzle 30, the glycerine becomes intimately mixed and with the steam is sprayed uniformly against the layer 15, therewith. The steam condenses on contact with the tobacco sheet, because the latter has been sufficiently cooled by the cooling device 8. Any steam, which is not condensed thereby escapes into the open atmosphere through a leakage point provided along an. edge of the hood 28. I Y

The sheet 50 is thus moistened again, and is removed I from the steel belt 1 bymeans of thescraper 9 and is then wound on to the bobbin 10. I

FIG. 2 shows, on a scale enlarged relative to FIG. 1, the section of the apparatus, generally indicated at 40, wherein the glycerine is mixed with the steam. The riser pipe 35 is provided with a spraying nozzle 41, which nozzle extends in the direction of flow of the steam as indicated by the arrow 42, andwhich is located within conduit 29. In this manner, the glycerine flow isinduced by the constriction 34 and enters the steam flow in an atomized state, which promotes intermixing. I

FIG.'.3 shows, in cross-section, a modified embodiment on a greatly enlarged scale relative to FIG. 1, a nozzle 45 corresponding in action with nozzle 30. In this modified embodiment, the constriction 34-is not utilized. The riser pipe for the glycerine enters a passage 46 in the body of the nozzle 45. Passage 46 flows into steam passage 48, at a constricted region 47 thereof. The glycerine is therefore not drawn into the steam flow by the venturi effect until shortly before atomization. Since only a small percentage by weight of glycerine is added to the steam, the short contact distance between glycerine and steam suffices for them to mix until contact is made with the sheet, and moreover, is sufficient for the glycerine to bein the gaseous phase by the time it contacts the tobacco layer.

SPECIFIC EXAMPLE I Sodium carbonate (100 g) is dissolved in water (400 l). Tobacco (100 kg), ground to an average granule size of 100 is then mixed into the solution. The mixture is stirred and ground whilst still wet into a pulp. Sodium carboxymethyl cellulose (1 kg) is mixed into the pulp as a bonding agent as are asbestos fibers (1 kg). A layer of this pulp is then applied to the upper surface of a steel belt, which also acts as a backing sheet to a depth of 3 mm. The belt is advanced at the rate of 0.3 m/sec. The layer of pulp applied thereto then passes through a drying chamber where hot air at a temperature of 60 C is blown at the surface thereof and is dried until the pulp has a moisture content of 10 percent by weight expressed as free water. Subsequently, the steel belt and the substantially dried layer, passes beneath a steam hood. Located substantially opposite the hood, i.e., below the steel belt, is a cooling device. The lOO kg of tobacco is sprayed with a total of 100 kg steam containing a total of 4 kg of glycerine added thereto as a plasticizer, the spraying being uniformly effected over the whole width of the layer. Using such quantities, the cooling device simultaneously receives the heat of evaporation of kg steam. The remaining heat is lost either by condensation of the steam on the hood or leakage thereof at the edge of the hood. The sheet thereby becomes thoroughly moistened and is permeated uniformly therethrough with glycerine. The sheet is then removed from the belt by means of a scraper. It is then cut into sections and may then be further processed.

The apparatus described hereinbefore can be modified in several ways without departing from the scope of the appended claims. For example, the cooling device need not be located in the position shown in the drawings. It may instead by located over the steel belt instead of beneath it. The arrangement shown is however, particularly favorable.

lclaim:

1. An apparatus for the production of a sheet of tobacco comprising a conveyor means, means for applying a mixture of powdered tobacco, water and a bonding agent to said conveyor means, means for setting said mixture, means for spraying said mixture and means for removing said mixture from said conveyor means wherein said means for spraying said mixture comprises a steam source, a steam conduit communicating with said source, a steam nozzle terminating said conduit, injection means for injecting an additive into said steam conduit, and cooling means, said cooling means being located opposite said spraying means, said cooling means and said spraying means being disposed on opposed sides of said conveyor means. I

2. An apparatus as defined in claim 1, wherein said steam conduit is provided with a constriction region and said injection means for said additive comprises a tank containing said additive, a riser pipe disposed below the surface of said additive contained in said tank and a nozzle terminating said riser pipe, said nozzle being located in said constriction region of said steam conduit.

3. An apparatus as defined in claim 1 wherein said steam nozzle is provided with a constriction region and said injection means for said additive comprises a tank containing said additive, a riser pipe disposed below the surface of said additive contained in said tank and a nozzle terminating said riser pipe, said nozzle being located in said constriction region of said steam nozzle.

l06009 I 003s 

1. An apparatus for the production of a sheet of tobacco comprising a conveyor means, means for applying a mixture of powdered tobacco, water and a bonding agent to said conveyor means, means for setting said mixture, means for spraying said mixture and means for removing said mixture from said conveyor means wherein said means for spraying said mixture comprises a steam source, a steam conduit communicating with said source, a steam nozzle terminating said conduit, injection means for injecting an additive into said steam conduit, and cooling means, said cooling means being located opposite said spraying means, said cooling means and said spraying means being disposed on opposed sides of said conveyor means.
 2. An apparatus as defined in claim 1, wherein said steam conduit is provided with a constriction region and said injection means for said additive comprises a tank containing said additive, a riser pipe disposed below the surface of said additive contained in said tank and a nozzle terminating said riser pipe, said nozzle being located in said constriction region of said steam conduit.
 3. An apparatus as defined in claim 1 wherein said steam nozzle is provided with a constriction region and said injection means for said additive comprises a tank containing said additive, a riser pipe disposed below the surface of said additive contained in said tank and a nozzle terminating said riser pipe, said nozzle being located in said constriction region of said steam nozzle. 